This program aims to determine the structure of proteins involved in cell membrane recognition, targeting, and adhesion, in order to establish the mechanism and specificity of their interactions. There are three principal areas under investigation. 1) C-type animal lectins are a large familty of Ca2+ dependent carbohydrate-binding proteins. We are studying C-type lectins that function in cell-cell adhesion in leukocyte trafficking (selectins) and others that participate in the innate immune response by recognizing carbohydrate structures present on pathogenic cell surfaces (mannose-binding proteins and the macrophage mannose receptor). 2) Interactions of catenins. Catenins are cytoplasmic proteins that link cadherin cell adhesion molecules to the cytoskeleton. The interactions of catenins are essential to intercellular adhesion in solid tissues, and their assembly in cell junctions is a dynamic and highly regulated process. Beta-catenin is also an essential component of the wnt signalling pathway that governs cell fate choice during embryogenesis. 3) Proteins that participate in the recognition and fusion of intracellular transport vesicles with their target membranes.